System and method for raising and lowering sidewalls of a collapsible storage container

ABSTRACT

The present invention discloses a novel apparatus and way to aid in the folding of a shipping container. One or more spring assemblies are provided to control the load applied during the folding process by applying a torque to a series of torsion springs and bar extending along at least a portion of the length of the container sidewall.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application claims priority to U.S. Provisional Patent Application Ser. No. 62/281,823 filed on Jan. 22, 2016.

TECHNICAL FIELD

The present invention relates generally to a shipping container. More specifically the present invention relates to a system and method for folding and unfolding walls of a shipping container.

BACKGROUND OF THE INVENTION

The shipping industry uses large cargo containers to ship cargo from one location to another in domestic and global commerce. Such containers are designed to be conveniently moved from one mode of transport to another across the land by road or on rail or over the sea. Such containers are sometimes referred to as “intermodal shipping containers” or “freight containers.” The use of such containers has essentially eliminated the need for manually transferring cargo from one vessel to another, or from one vehicle or railcar to another in the effort to deliver the cargo to its final destination.

Today, cargo containers are generally standardized by internationally recognized standards, and by national domestic standards with respect to dimensions and structure. Thus, the standard containers can be securely arranged in vertical stacks in side-by-side and end-to-end relationship with each other, and can be handled most effectively when transferring from one mode of transport to another regardless of their source or destination.

Often, these containers must be transported empty from one delivery point to the next location where cargo is available for shipment. Transport of empty containers costs the shipper money and erodes profits since transport of each such container incurs handling cost and occupies valuable space which could otherwise be used to ship a revenue producing container loaded with cargo. Additionally, the shipping of both loaded and empty containers creates problems such as how to arrange the lighter, empty containers and the heavier, loaded containers aboard ships in such a manner that the safety of the ships is not compromised. Beyond safety issues, the shipment of empty containers causes monetary losses for shippers, losses which result in either substantial financial impact on the shipper or increased charges to customers for the handling and transport of loaded containers. Similar cost disadvantages apply when shipping empty containers over road or by rail.

Long ago shippers recognized that significant economic savings in shipping could be realized if empty containers could be “folded” so as to occupy a substantially smaller space, so that less space need be sacrificed in the transporting of empty containers. Such an effort presently exists only for the “open frame” or flat rack type containers. To that end, the prior art proposed many foldable or nesting cargo containers of the enclosed types intended to reduce the space required for their shipment when empty. While such prior art foldable containers have been proposed, the market has not embraced the prior art containers as a substitute for the standard, non-foldable cargo containers due to these prior art foldable containers not meeting ISO standards and ISO certifications for being water proof.

A shortcoming of foldable containers of the prior art is the lack of structural designs which enable or facilitate the folding and un-folding of such containers in a simple and effective manner with commonly available equipment. More specifically, foldable containers of the prior art do not provide an easy and controllable way of folding and unfolding the walls of the container. The walls of the these types of large intermodal shipping containers are typically fabricated from corrugated steel and for a standard 40 High Cube container, these walls can weigh upwards of 1500 pounds, thus making their raising and lowering extremely difficult and dangerous.

Prior collapsible containers have walls which include lifting mechanisms to aid in the raising of the container walls. One such example is a lifting bar, such as that disclosed in U.S. Pat. No. 9,022,242 assigned to Holland Container Innovations, and depicted generally in FIGS. 1 and 2. In this configuration, lever arm 8 extends at a ninety degree angle relative to wall 2 and is connected to wall 2 by connecting member 10. The lever arm 8 provides a point a distance away from the wall 2 where a manual force can be applied to create a moment to help raise the wall 2, causing it to pivot about hinge 4. While this mechanism provides a way of lifting the sidewalls through a lever type arrangement, this device requires a large amount of force applied to the lifting bars to overcome the weight of the container sidewalls. However, such a configuration also has disadvantages including the labor and force required to erect the container.

SUMMARY

The present invention discloses systems and methods for folding and erecting a shipping container. More specifically, in an embodiment of the present invention, a spring assembly is provided for use in supporting the folding of the sidewalls of a collapsible container. The spring assembly comprises a bar extending a length along the sidewall with the bar being oriented parallel to an axis of rotation for the sidewall. The spring assembly also comprises a plurality of torsion springs arranged about the bar with each spring having a first end generally parallel to the bar and a second end generally perpendicular to the bar. The first end of the spring, which is parallel to the bar and rigidly connected to the bar by the washer, transmits the torque of the spring through the rod, into the hinge and then into the sidewall. The second end of the spring, or perpendicular end, is restricted by the base beam or external cover allowing the rotation of the sidewall to rotate the spring and store the torque generated.

In an alternate embodiment of the present invention, a collapsible container is provided comprising a base panel, a roof panel spaced a distance from the base panel and generally parallel to the base panel, and a pair of sidewalls extending between the base panel and the roof panel, where the sidewalls are rotatably coupled to the base panel along a bottom edge of the sidewalls. The container also has a door panel and front panel extending between the pair of sidewalls, with the door panel and the front panel being rotatably coupled to the roof panel. One or more spring assemblies is positioned near the bottom edge of each sidewall and in contact with the sidewalls, where the spring assembly comprises a bar extending a length along the sidewall and a plurality of torsion springs coupled to the bar. Upon a folding of the sidewalls of the container, the sidewalls rotate to be generally parallel to the base panel, and in doing so, contact the plurality of torsion springs, causing the springs to twist and store energy produced by the sidewall rotation.

The present invention also provides a method of folding a collapsible container in accordance with the associated systems discussed herein. Accordingly, the present invention also extends to a method of erecting a shipping container from its folded condition.

It is an object of the present invention is to provide a novel, foldable, enclosed shipping container where the shipping container is folded utilizing a torsional spring system along at least a portion of the container sidewalls. The weight of the sidewalls is used to the advantage of the folding and unfolding processes by increasing the tension in the springs during the folding process, such that upon erecting the container, tension in the springs is used to help raise the container sidewalls.

In an embodiment of the present invention, a locking mechanism is provided for use with the spring assembly in order to provide a way of securing the container sidewalls when in a collapsed configuration. The locking mechanism comprises an adjustable strap that attaches to a top edge of the container sidewall and can also retract into a stored position when not in use.

Additional advantages and features of the present invention will be set forth in part in a description which follows, and in part will become apparent to those skilled in the art upon examination of the following, or may be learned from practice of the invention. The instant invention will now be described with particular reference to the accompanying drawings.

BRIEF DESCRIPTION OF THE SEVERAL VIEWS OF THE DRAWINGS

The present invention is described in detail below with reference to the attached drawing figures, wherein:

FIG. 1 is a cross section view of a portion of a container of the prior art.

FIG. 2 is a cross section view of a container of the prior art.

FIG. 3 is a perspective view of a collapsible container in accordance with an embodiment of the present invention.

FIG. 4 is a perspective view of the container of FIG. 3 in a collapsed, or folded, condition.

FIG. 5 is perspective view of the collapsible container of FIG. 3, including a spring assembly in accordance with the present invention.

FIG. 6 is a partial perspective view of a portion of the collapsible container of FIG. 5 in accordance with an embodiment of the present invention.

FIG. 7 is a perspective view of the collapsible container of FIG. 5 depicting a sidewall folding inward in accordance with an embodiment of the present invention.

FIG. 8 is a partial perspective view of a portion of the collapsible container of FIG. 5 depicting a sidewall folding inward in accordance with an embodiment of the present invention.

FIG. 9 is a perspective view of an alternate embodiment of the present invention.

FIG. 10 is a perspective view of the collapsible container of FIG. 9 depicting a sidewall folding inward.

FIG. 11 is a detailed perspective view of a portion of the collapsible container of FIG. 9.

FIG. 12 is a detailed perspective view of a portion of the collapsible container of FIG. 10 depicting a sidewall folding inward.

FIG. 13 is an elevation view of a spring assembly in accordance with an embodiment of the present invention.

FIG. 14 is a perspective view of the spring assembly and gear mechanism of FIG. 13.

FIG. 15 is an alternate elevation view of the spring assembly in accordance with an embodiment of the present invention.

FIG. 16 is a cross section view through the gear mechanism of a collapsible container in accordance with an embodiment of the present invention.

FIG. 17 is a partial cross section view of a collapsed container and locking mechanism when not in use.

FIG. 18 is a partial cross section view of a collapsed container depicting a locking mechanism for securing a sidewall in a collapsed configuration.

DETAILED DESCRIPTION

The present invention discloses a system and method for improving the foldable nature of a shipping container. More specifically, embodiments of the present invention relate to systems and methods for improving the way in which the walls of the container are folded or erected. A discussion of the present invention follows and relates to FIGS. 3-16.

Referring now to FIG. 3, a collapsible container 100 in accordance with an embodiment of the present invention is shown in its upright, erect, configuration while FIG. 4 shows the container 100 in its collapsed state. The container 100 comprises a base panel 102, a roof panel 104 spaced a distance from the base panel 102, with the roof panel 104 generally parallel to the base panel 102. A pair of opposing and parallel sidewalls 106 extends between the base panel 102 and roof panel 104 where the sidewalls 106 are rotatably coupled to the base panel 102 along a bottom edge 108 of the sidewalls 106. The container 100 also includes a door panel 110 and front panel 112 that extend between the sidewalls 106. However, the door panel 110 and front panel 112 are rotatably coupled to the roof panel 104.

The collapsible container 100 also comprises a spring assembly 120, as depicted in FIGS. 5-18. The spring assembly 120 in turn can comprise a primary spring assembly, arranged in a single axis as shown in FIGS. 5-8 or a primary and secondary spring assembly arrangement as shown in FIGS. 9-15, depending on the container configuration. The spring assembly 120 is positioned proximate the bottom edge 108 of the sidewalls 106. The spring assembly 120 operates in conjunction with the plurality of hinges 122 as shown in FIGS. 6, 8, and 11-15. The hinges 122 connect the sidewall 106 to the base panel 102. As depicted herein, the spring assembly 120 can be positioned in the same axis as that about which the hinges 122 rotate. Alternatively, the spring assembly 120 (primary and/or secondary) can have one or both assemblies located along an axis that is parallel to the hinges 122.

One or more bars 124 extend along at least a portion of the sidewall 106 and a plurality of torsion springs 126 are coupled to the one or more bars 124 as shown in FIGS. 12, 13 and 15. In the configuration depicted in FIGS. 5 and 9, the bar 124 extends the length of the sidewall 106 and is rigidly secured to the hinges 122. In an alternate embodiment, the bar 124 is comprised of multiple bars that positioned end to end and together extend approximately the length of the sidewall 106. More specifically, and with reference to FIGS. 11-15, the torsion springs 126 are connected to the bar 124 by way of a washer 128 (see FIG. 15) where the washer 128 is rigidly secured to the bar 124, by a means such as welding. Referring to FIG. 15, the torsion springs 126 have a first end 126A that is oriented parallel to the bar 124 and is captured by the bar 124 as the first end 126A slides into a receiving hole (not shown) in the washer 128. The torsion springs 126 also have a second end 126B that is generally perpendicular to the bar 124. For the second end 126B, this end can face one of two ways, either upwards or downwards from the bar 124. As shown in FIG. 15, this orientation alternates in order to counteract the reaction forces that the springs 126 exert on the bar 124.

The second portion of the torsion spring 126B is in contact with a portion of the sidewall 106 such that upon a lowering, or folding, of the sidewalls 106 in towards the base panel 102, the sidewalls 106 rotate to be generally parallel to the base panel 102. As a result, the sidewalls 106 apply a force to the second portion 126B of the torsion springs, causing the torsion springs 126 to twist and impart a force to the bar 124. The torsion springs 126 and bar 124 absorbs the force applied thereto as the sidewalls 106 are folded in towards the base panel 102. The energy imparted in the springs 126 and bar 124 can then be utilized to assist in raising the sidewalls 106 from the folded position.

Typically, a secondary spring assembly is implemented when the moment torque required for the sidewall 106 is greater than what the primary torsion spring torque can produce. When a secondary spring assembly is utilized, as shown in FIGS. 9-15, a second bar 130 and plurality of torsion springs 132 are arranged parallel to the bar 124 and torsion springs 126. The second bar 130 and torsion springs 132 operate in the same way as the bar 124 and torsion springs 126. In this configuration the parallel rows of spring assemblies are coupled together through a gear mechanism 140 as shown in FIGS. 11-16. The secondary spring assembly is connected via a set of three gears 140A, 140B, and 140C which translates the rotation of the sidewall 106 from the main spring assembly to the secondary spring assembly, as shown in FIGS. 14 and 16. The gear mechanism 140 translates the load from one assembly to the other so they act in parallel. This system provides the additional torque needed at the lower 45 degrees of rotation where the first spring assembly can struggle. The present invention is not limited to two spring assemblies coupled together by a single gear mechanism. It is possible that multiple rows of spring assemblies can be utilized, requiring multiple gear mechanisms.

As depicted in FIGS. 11-15, the second bar 130 and torsion springs 132 of the secondary spring assembly do not extend the entire length of the sidewall 106 and are located towards the ends of the sidewall 106. This arrangement is but one acceptable configuration for the secondary spring assembly. Alternate arrangements may include the secondary spring assembly extending the length of sidewalls 106 or an alternate length. In this embodiment, the secondary spring assembly is located beneath the primary spring assembly and is coupled to the primary spring assembly (bar 124 and springs 126) by the gear mechanism 140 as shown in FIGS. 11-16. The exact size, length, and quantity of springs 132 required as part of the secondary spring assembly will depend on factors such as the container size, weight of the sidewalls, etc. Presently, the second bar 130 and springs 132 are located at each end of the sidewall 106 primarily because the ends of the sidewalls 106 are slightly heavier than the middle portion of the sidewalls 106. The present invention is not limited to the configuration depicted herein, and depending on a variety of design factors, may also include additional spring assemblies.

In an embodiment of the present invention, an adjustability function is provided for the torsional springs 126 and 132. That is, the springs can be pre-torqued from one to thirty degrees, which allows for an operator of the collapsible container to reach the required torque necessary to open the sidewall 106 from the collapsed position. The amount of torque required varies depending on the final weight of the sidewall. Due to manufacturing tolerances the overall weight of the sidewall can vary by up to 75 pounds, which changes the moment of the panel, which in turn, correlates to the torque required. Pre-torquing the springs 126 and 132 also provides a safety measure when the folding process is first initiated by helping to prevent the sidewall 106 from falling prematurely when it is no longer connected to the roof panel 104 or the door or front panels 110 or 112. The torsion springs 126 and 132 are adjustable by this pre-torquing, which occurs at the original assembly of the collapsible container. Alternatively, the torsion springs 126 and 132 are also adjustable after the initial container assembly through an external set screw, which acts on the vertical leg of the spring through the base beam so as to change the pre-torque angle. Also, the springs 126 and 132 can be aligned at a desired angular position to achieve a desired amount of torque so as to be pre-torqued or slack when the sidewall 106 is in a vertical position.

Referring back to FIGS. 11-15, the springs 126 and 132 are spaced generally evenly along the respective bars 124 and 130 and equidistant between the hinges 122. Such a spacing allows for equal distribution of the force applied by the sidewalls 106 onto the torsion springs.

The torsion springs 126 and 132 are sized to be coaxial with the bar 124 and 130, as shown in FIGS. 7 and 8. Each of the springs 126 and 132 have between six and twelve active coils and a spring rate ranging from 6 lbf.-in./deg. to 11.75 lbf.-in./deg.

The present invention also incorporates friction reduction technology in order to facilitate torsion spring effectiveness in the folding of the sidewalls 106. For example, Teflon® bushings can be placed between the bar 124/130 and the receiving position of the base beam where the bar 124/130 rotates to reduce the friction interface at this point of rotation.

Another feature of the present invention is a locking mechanism 150 which is used for securing the sidewalls 106 in place when the container is in a folded position. Referring to FIGS. 17 and 18, the container 100 includes one or more locking mechanisms 150, each having a strap 152 that captures a rigid pin 154, which is located along a top portion of the sidewall 106. The strap 152 recesses into the base panel 102 when not in use, as shown in FIG. 17. Once the sidewall 106 is collapsed, the strap 152 is pulled out from its recess and connected to the pin 154 on the top of sidewall 106. The resistance of the sidewall 106 keeps the strap 152 taught when it is extended to secure the sidewall. The strap 152 is preferably fabricated from a nylon or other durable and flexible material in order to withstand the environmental and operating conditions.

As used herein, the term “panel” can comprise a single section or in the alternative can be comprised of multiple sections secured together by an acceptable process, such as welded together to form a weldment.

The foldable container 100 of the present invention is folded in a way such that it is capable of being stacked vertically multiple units high when not in use. The container geometry described herein permits the stacking of the containers as described in co-pending U.S. patent application Ser. No. 14/829,275.

The foldable container 100 of the present invention is fabricated from materials capable of withstanding a variety of weather elements and operating conditions. At least the exterior surfaces of the roof panel 104, base panel 102, front panel 112, door panel 110, and sidewalls 106 are fabricated from corrugated metal, such as CorTen® steel. For example, CorTen® A, also known as A588, is an industry standard acceptable material as this material provides excellent corrosion resistance. This material capability is necessary given the harsh weather conditions experienced by the foldable container, including but not limited to salt water, sea air, rain, snow, and extreme heat and cold. Internal walls of the foldable container 100 can be corrugated metal or can be lined with other materials as desired by the owner/operator of the foldable container 100. Such container material provides the necessary protection of the internal spring assembly components whether the container is in its erect or folded state.

The materials of the spring assembly are typically higher strength steels. For example, the bar may be made from 1144 while the washer may be made from higher strength steel such as ASTM A514.

The present invention is applicable to a variety of standard intermodal shipping containers. For example, the folding container and associated spring assembly technology can be configured to accommodate various container lengths as used in the intermodal transport industry including, but not limited to, containers of 10 feet, 20 feet, 24 feet, 40 feet, 48 feet, and 53 feet in length.

While the invention has been described in what is known as presently the preferred embodiment, it is to be understood that the invention is not to be limited to the disclosed embodiment but, on the contrary, is intended to cover various modifications and equivalent arrangements within the scope of the following claims. The present invention has been described in relation to particular embodiments, which are intended in all respects to be illustrative rather than restrictive.

From the foregoing, it will be seen that this invention is one well adapted to attain all the ends and objects set forth above, together with other advantages which are obvious and inherent to the system and method. It will be understood that certain features and sub-combinations are of utility and may be employed without reference to other features and sub-combinations. This is contemplated by and within the scope of the claims. 

1. A collapsible container comprising: a base panel; a roof panel spaced a distance from the base panel and generally parallel to the base panel; a pair of sidewalls extending between the base panel and the roof panel, the sidewalls rotatably coupled to the base panel along a bottom edge of the sidewalls; a door panel and a front panel extending between the pair of sidewalls, the door panel and the front panel rotatably coupled to the roof panel; a spring assembly positioned proximate the bottom edge of each sidewall and in contact with the sidewalls, the spring assembly comprising one or more bars extending approximately a length of the sidewall and a plurality of torsion springs coupled to the one or more bars; wherein upon a folding of the sidewalls of the container, the sidewalls rotate to be generally parallel to the base panel, thereby causing the plurality of torsion springs to rotate and store energy produced by the sidewall rotation in the springs.
 2. The collapsible container of claim 1 further comprising a locking mechanism for securing the sidewalls of the container in a folded condition.
 3. The collapsible container of claim 2, wherein the energy stored through twisting in the plurality of torsion springs is utilized to assist in raising the sidewalls of the container from a folded condition.
 4. The collapsible container of claim 1, wherein the spring assembly comprises a plurality of torsion springs arranged in one or more rows, where the torsion springs have a first end oriented parallel to the bar and captured by a washer secured to the bar and a second end generally perpendicular to the bar.
 5. The collapsible container of claim 4, wherein the one or more rows of springs comprises two rows, with a first row extending approximately a length of the sidewall and the plurality of springs positioned coaxial with the bar.
 6. The collapsible container of claim 5, wherein a second row of springs extends along a portion of the length of the sidewall.
 7. The collapsible container of claim 6 further comprising a gear mechanism for coupling the second row of springs to the first row of springs.
 8. The collapsible container of claim 1, wherein the plurality of torsion springs of the spring assembly are equally spaced between hinges connecting the sidewalls to the base panel.
 9. The collapsible container of claim 1, wherein each of the torsion springs each have six to twelve active coils.
 10. The collapsible container of claim 9, wherein the torsion springs have a spring rate ranging from 6 lbf.-in./deg. to 11.75 lbf.-in./deg.
 11. The collapsible container of claim 1 wherein the spring assembly further comprises an adjustment mechanism for adjusting a pre-torque to the plurality of torsion springs.
 12. A spring assembly for use in supporting folding of sidewalls of a collapsible container comprising: one or more bars extending approximately a length of a sidewall of the collapsible container, the one or more bars being parallel to an axis of rotation about which the sidewall rotates; a plurality of torsion springs arranged about the bar and having a first end generally parallel to the bar and a second end generally perpendicular to the bar, the first end of each torsion spring coupled to the bar, and the second end in contact with a portion of the sidewall; wherein upon folding of the sidewalls of the collapsible container, the sidewalls rotate to be generally parallel to a base panel, thereby causing the plurality of torsion springs to twist and store energy produced by a twisting of the springs.
 13. The spring assembly of claim 12, wherein the spring assembly is coaxial to the axis of rotation.
 14. The spring assembly of claim 12, wherein the energy stored through twisting in the plurality of torsion springs is utilized to assist in raising the sidewalls of the container from a folded condition
 15. The spring assembly of claim 12, wherein the plurality of torsion springs are positioned in one or more rows of springs with a first row extending approximately a length of the sidewall and the plurality of springs positioned coaxial with the bar.
 16. The spring assembly of claim 15, wherein a second row of springs extends along a second bar parallel to the bar, the second bar extending along a portion of the length of the sidewall.
 17. The spring assembly of claim 16 further comprising a gear mechanism for coupling the second row of springs to the first row of springs.
 18. The spring assembly of claim 12, wherein the plurality of torsion springs are equally spaced between hinges connecting the sidewalls to a base panel of the container.
 19. The spring assembly of claim 12, wherein each of the torsion springs each have six to twelve active coils.
 20. The spring assembly of claim 19, wherein the torsion springs have a spring rate ranging from 6 lbf.-in./deg. to 11.75 lbf.-in./deg.
 21. The spring assembly of claim 12 further comprising an adjustment mechanism for adjusting a pre-torque to the plurality of torsion springs.
 22. A system for controlling the folding of a sidewall for a collapsible storage container comprising: A primary spring assembly comprising: a first bar extending approximately a length of a sidewall of the collapsible container, the first bar being parallel to an axis of rotation about which the sidewall rotates; a first plurality of torsion springs arranged about the first bar and having a first end generally parallel to the first bar and a second end generally perpendicular to the first bar, the first end of each torsion spring coupled to the first bar, and the second end in contact with a portion of the sidewall; A secondary spring assembly positioned parallel to the primary spring assembly, the secondary spring assembly comprising: a second bar extending along at least a portion of the sidewall of the collapsible container, the second bar being parallel to an axis of rotation about which the sidewall rotates; a second plurality of torsion springs arranged about the second bar and having a first end generally parallel to the second bar and a second end generally perpendicular to the second bar, the first end of each torsion spring coupled to the second bar by way of a washer, and the second end in contact with a portion of the sidewall; A gear mechanism comprising first, second and third tooth gears configured in a generally vertical arrangement to couple movement of the second bar to movement of the first bar.
 23. The system of claim 22, wherein the primary spring assembly is located coaxial to the axis of rotation and the secondary spring assembly is located along an axis parallel to the axis of rotation.
 24. A method of storing energy for use in assembling a storage container comprising: rotating a sidewall of the storage container, the sidewall having a spring assembly comprising a bar extending along a length of the sidewall and a plurality of torsion springs arranged about the bar, where the torsion springs are coupled to the bar at a first end of the spring; contacting a second end of the torsion springs with the sidewall; and, twisting the torsion springs as the sidewall is lowered to a generally horizontal position.
 25. The method of claim 24, wherein the torsion springs have a spring rate ranging from 6 lbf.-in./deg. to 11.75 lbf.-in./deg. 